In the field of automation, there are many devices, such as processing machines, wherein a work piece is conveyed or moved in various directions. This requires cables to supply power and transmit control signals which are long enough and flexible so that displacement of the mechanism can be accomplished. It is generally required that a plurality of covered wires be provided for the traveling mechanism and it is not unusual to have in excess of three such cables joined together. In the past, if changes in design required additional cables, they could not be accommodated while, at the same time, maintaining the desired degree of freedom of motion.
Referring to FIGS. 7 and 8, when flexibility in the design of the device is desired, multiple individually covered wires 1 are grouped together and loosely passed through hollow cable cover 4 which is formed from a plurality of protective rings 2. Rings 2 are rotatably connected to one another by pins 3. Thus, cable cover 4 can flex freely, in the manner of caterpillar treads, within the available space in the device. As shown in FIG. 8, covered wires 1 are protected from external forces while remaining flexible.
The foregoing construction, however, possesses certain drawbacks. Repeated movements of the traveling mechanism can result in covered wires 1 crossing each other and/or becoming overlapped, as shown in FIG. 9. This is possible, even if covered wires 1 are loosely inserted in cable cover 4, with covered wires 1 in flat side-by-side arrangement. Thus, when such wires shift, they can end up lying on a path which is different from that origin ally intended. Therefore, if the path is longer than that initially designed, an excessive force can be applied to the wires and reduce their life span. In more extreme cases, they can even be broken.
In order to solve this problem, as shown in FIG. 10, positioning wall 7 has been inserted in each protective ring 2. Insertion openings 6 ar e formed thereon so that each individual covered wire 1 is permanently located therein. However, this arrangement does not permit the number of insertion openings 6 to be changed once cable cover 4 has been fabricated. Hence, desirable flexibility is lost and the presence of positioning walls 7 increases the cost of cable cover 4.